The 772 was last made in 1961, and is a good rifle although there is a recall for a new trigger group from Remington. One of the main things I ask myself before I buy a rifle is what do I want to use it for? Ammo type is a main consideration unless you want it for it's antique or historical value.
300 Savage ammo has better ballistics that the beloved 30-30. This made it a popular cartage for lever action rifles 60-70 years ago. Today it has fallen out of favor and as you said, factory ammo is available but expensive. If you want a rifle that uses less expensive ammo then sell your 722 and find a rifle in a more popular and cheaper ammo. As for the accuracy concerns about your 722, carefully inspect the barrels bore. A lot can happen to the barrel is 60 years, is it leaded or is the bore damaged? Slug the barrel to find out the internal size of the barrel, it may just be worn out.
If the bore is worn, you might be able to restore it's accuracy by reloading with slightly oversized bullets. But until you know why your rifle is inaccurate, I wouldn't be buying any reloading dies yet.